Discussions By Condition: I cannot get a diagnosis.

Bradycardia/Max Heart Rates

I haven't been diagnosed with bradycardia but i do have a slow heart rate. I am 25 years old and i am in good shape. I don't think it is anything other than being in good shape. However, I find it hard to get my heart rate up to my max heart rate during exercise which i believe is (220-25)x80%. Is this normal since i have a slow resting heart rate to begin with?